Fluid-containing bodies such as pipe are widely used for delivering fluid from place to place. In order to control this operation and/or for exploiting the fluid for electric energy generation, it is sometimes required to introduced various devices into the pipe while being under fluid pressure.
There are many known techniques for introduced a device into a pipe under fluid pressure. One such technique is hot tapping. In general, typical applications of hot tapping include making a branch connection, initiating a bypass, allowing performance of a line stop and introducing a device into a pipe under pressure. Components required to perform a hot tap normally include a fitting designed to contain system pressure, a valve used to control the new connection and a drilling or tapping machine.
One example of a prior art reference is U.S. Pat. No. 2,870,629 which discloses an apparatus for moving an element into and from a vessel containing liquid under pressure.